This disclosure is related to sealants, techniques for applying sealants, and sealant articles.
Sealants are widely used for a variety of applications. For example, sealants can be used to provide a seal between articles against penetration of outside materials such as liquids, gases, or solids. Sealants are often used in conjunction with fasteners used to connect articles together. For example, sealant is often applied to threaded connectors such as screws or bolts to provide a bond between male and female threaded members to inhibit loosening of the threaded connector that can be caused by vibration or impact. In some cases, articles comprising different metal compositions are joined together, such as an aluminum structural component and a stainless steel fastener. When the different metal compositions (or a metal composition and a non-metallic electrically conductive material (e.g., carbon)) have different electrode potentials (i.e., one metal is more noble than another metal), the presence of water between the articles can act as an electrolyte and promote an electrochemical reaction leading to galvanic corrosion. In such cases a sealant between the articles of different electrode potential can be used to help protect against galvanic corrosion by resisting penetration of water between the articles.
Sealants can be applied to articles by various techniques, including brush application or various types of injection techniques. In many cases, the sealant is a curable composition that is applied in a liquid or flowable state, followed by curing to a solid or hardened state. Many sealants such as two-component reactive sealants, or sealants having a chemical curing reaction initiated by exposure to oxygen or atmospheric moisture have a limited time period after application before the cure reaction is complete. This often necessitates application of the sealant at the time of or shortly before assembly of the article(s) to be sealed. Even sealants that undergo a curing reaction whose initiation can be controlled, e.g., by later application of heat or radiation, can have a limited time period during which they maintain flow characteristics sufficient to allow for compression of the sealant between the articles being sealed in order to provide a tight contiguous seal bond.